This invention relates generally to inflatable restraint systems and, more particularly, to filter assemblies and related combinations used in or in association with the generation of gas via the reaction of a solid form of gas generant material.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an “airbag cushion,” that is inflated or expanded with gas when the vehicle encounters sudden deceleration, such as in the event of a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Such systems typically also include one or more crash sensors mounted on or to the frame or body of the vehicle to detect sudden decelerations of the vehicle and to electronically trigger activation of the system. Upon actuation of the system, the cushion begins to be inflated in a matter of no more than a few milliseconds with gas produced or supplied by a device commonly referred to as an “inflator.”
Many types of inflator devices have been disclosed in the art for the inflating of one or more inflatable restraint system airbag cushions. Inflator devices which form or produce inflation gas via the combustion of a gas generating material, i.e., a “gas generant,” such as in the form of a pyrotechnic material, are well known. It is also known that certain of such inflator devices may use such generated gas to supplement stored and pressurized gas by the addition of high temperature combustion products, including additional gas products, produced by the burning of the gas generating material to a supply of the stored, pressurized gas. In some cases, the combustion products produced by the burning of a gas generating material may be the sole or substantially the sole source for the inflation gas issuing forth from a particular inflator device.
It is common that inflator devices include an initiator, such as a squib, and an igniter. In practice, upon receipt of an appropriate triggering signal from a crash or other selected deceleration sensor, the initiator activates causing the rapid combustion of the igniter material, which, in turn, ignites the gas generant. The burning of the pyrotechnic (gas generating) and initiation materials, however, almost invariably results in the undesired production of particulate material. In view thereof, various approaches have been attempted and/or suggested to filter or otherwise remove particulate matter from such produced gas.
In addition to filter devices of varying complexity, typical inflator assemblies devices require the inclusion of additional hardware or component parts such as a retainer disk or, as sometimes referred to, a retainer lid, for example, to permit or allow for proper and desired containment of the gas generant material within the inflator assembly. As will be appreciated, the presence and inclusion within an inflator device of additional hardware or component parts for each of the purposes of filtration and gas generant containment typically undesirably complicates one or more of the design, assembly, and operation of the resulting inflator device. Consequently, one or more of the cost, weight and complexity of a particular inflator assembly may be greater than otherwise desired.
In view of the above, there is a need and demand for a gas generant filter assembly and related combinations which desirably avoid or minimize the requirement for additional component parts and/or otherwise reduce or minimize one or more of the cost, weight and complexity of assembly, preferably without detrimentally impacting either or both performance and operation.